The purpose of this project is to develop a set of techniques which may allow one to clone specific eukaryotic genes using only antibodies as the screening probe. Our strategy is to construct a human genomic DNA library using a unique cosmid expression vector, transfer these cloned sequences to cultured eukaryotic cells, detect those cell colonies producing the protein of interest and finally, rescuising the plasmid, with its cloned sequence, from the expanded colony. We are currently constructing a human genomic library using a cosmid vector containing the bovine papilloma virus genome. Experiments are underway to optimize the transformation of cultured eukaryotic cells with plasmid DNA as well as experiments to optimize the detection of heterologous antigens in individual cultured cells. When these techniques are available, they should permit the cloning of eukaryotic genes which would otherwise be inaccessible.